Flexible roll forming method

Abstract

In accordance with an exemplary embodiment of the present invention, a flexible roll forming method for roll forming a beam of a predetermined shape by bending a material fed to a plurality of roll forming units each having upper and lower forming rolls in succession, and for roll forming the beam by feeding the material to a flexible roll forming unit having upper and lower forming rolls disposed on left/right sides of a process direction and both side upper and lower forming rolls disposed to vary positions in a lateral direction of the process and angles from a process direction, respectively, to cause flexible bending of the material in succession over multiple stages, is provided.

What is claimed is: 
     
         1 . A flexible roll forming method for roll forming a beam of a predetermined shape by bending a material fed to a plurality of roll forming units each having upper and lower forming rolls in succession, and
 for roll forming the beam by feeding the material to a flexible roll forming unit having upper and lower forming rolls disposed on left/right sides of a process direction and both side upper and lower forming rolls disposed to vary positions in a lateral direction of the process and angles from a process direction, respectively, to cause flexible bending of the material in succession over multiple stages.   
     
     
         2 . The flexible roll forming method of  claim 1 , wherein the material is
 a blank with symmetry in a left/right direction with respect to a length direction center line having a width that is varied along the length direction on the whole.   
     
     
         3 . The flexible roll forming method of  claim 1 , wherein the material is
 a blank with symmetry in a left/right direction with respect to a length direction center line having a straight portion with a fixed width, and an expanded portion with a width that becomes larger as the expanded portion goes more in the length direction.   
     
     
         4 . The flexible roll forming method of  claim 1 , wherein
 the material is   a blank with symmetry in a left/right direction with respect to a length direction center line having a straight portion with a fixed width, an expanded portion with a width that becomes larger as the expanded portion goes more along the length direction, and a curved portion connecting the straight portion to the expanded portion with a curved line.   
     
     
         5 . The flexible roll forming method of  claim 1 , wherein
 the flexible bending   includes a step of flexible roll forming the beam having different widths along the length direction and flanges on opposite sides thereof by bending of predetermined widths of opposite edges of the material having different widths along the length direction in succession over multiple stages.   
     
     
         6 . The flexible roll forming method of  claim 5 , wherein
 the flexible bending   further includes the step of roll forming the beam to have side portions by bending of opposite sides of the beam with respect to the length direction center line along the length direction of the blank in succession over multiple stages.   
     
     
         7 . A flexible roll forming method of roll forming a beam of a predetermined shape by bending a material fed to a plurality of roll forming units each having upper and lower forming rolls in succession, and
 of roll forming flanges on opposite sides of a blank with symmetry in a left/right direction with respect to a length direction center line, having a straight portion with a fixed width, an expanded portion with a width that becomes larger as the expanded portion goes more in the length direction, and a curved portion connecting the straight portion to the expanded portion with a curved line, with a flexible roll forming unit having upper and lower forming rolls disposed with symmetry in left/right sides of a process direction and both side upper and lower forming rolls disposed to be movable forward/backward in a lateral direction of the process and to vary angles from a process direction, respectively, by bending predetermined widths of opposite edges of the blank with respect to a length direction center line along a length direction of the blank in succession over multiple stages,   wherein both side upper and lower forming rolls have   positions in a lateral direction of the process fixed at the straight portion of the blank, and angles at a right angle to the process direction to form the flanges by roll forming, respectively,   the positions in the lateral direction of the process fixed at the curved portion, the angles from the process direction varied up to angles the same as the expanded portion, to form the flanges by roll forming, respectively, and   the angles from the process direction at the expanded portion maintained the same as angles of the expanded portion, and the positions in the lateral direction of the process which become larger as the expanded portion goes along the length direction of the blank to form the flanges on the opposite sides, to cause flexible roll forming of the formed beam having different widths along the length direction.   
     
     
         8 . The flexible roll forming method of  claim 7 , wherein
 the flexible roll forming   further includes the step of making roll forming the formed beam to have rectangular side portions by bending opposite sides of the formed beam with respect to the length direction center line along the length direction of the blank in succession over multiple stages.   
     
     
         9 . A flexible roll forming method of roll forming a beam of a predetermined shape by bending a material fed to a plurality of roll forming units each having upper and lower forming rolls in succession, the flexible roll forming method comprising:
 a first step of roll forming flanges on opposite sides of a blank with symmetry in a left/right direction with respect to a length direction center line, having a straight portion with a fixed width, an expanded portion with a width that becomes larger as the expanded portion goes more in the length direction, and a curved portion connecting the straight portion to the expanded portion with a curved line, with a flexible roll forming unit having upper and lower forming rolls disposed with symmetry in left/right sides of a process direction and both side upper and lower forming rolls disposed to be movable forward/backward in a lateral direction of the process and to vary angles from a process direction, respectively, by bending predetermined widths of opposite edges of the blank with respect to a length direction center line along a length direction of the blank in succession over multiple stages,   wherein both side upper and lower forming rolls have positions in a lateral direction of the process fixed at the straight portion of the blank, and angles at a right angle to the process direction to form the flanges by roll forming, respectively, the positions in the lateral direction of the process fixed at the curved portion, the angles from the process direction varied up to angles the same as the expanded portion, to form the flanges by roll forming, respectively, and the angles from the process direction at the expanded portion maintained the same as angles of the expanded portion, and the positions in the lateral direction of the process which become larger as the expanded portion goes in along the length direction of the blank to form the flanges on the opposite sides, to cause flexible roll forming of the formed beam having widths different along the length direction; and   a second step of roll forming the beam to have rectangular side portions by bending of opposite sides of the formed beam with respect to the length direction center line along a length direction of the blank in succession over multiple stages after the first step,   wherein, in a final step of the first step, the roll forming occurs in a state in which the upper and lower forming rolls are in rolling contact with a reference surface of the blank and respective surfaces of the flanges at the same time.